Anticonvulsive activity of indenoimidazolidinones and related heterocyclic compounds in mice.

A series of substituted cyclic ureides and related compounds, one of them a thio analog, were synthesized by condensing ninhydrin with urea, thiourea, dimethylurea or other aromatic or bifunctional agents. When tested against seizures induced in mice by the chemoconvulsant Metrazol or against audiogenic seizures, four compounds decreased either the incidence or the severity of convulsive manifestations and protected from mortality in seizures. The effective compounds were not toxic at the administered level (150 mg/kg) and produced few observable sedative effects.